Is There a Doman Wide Quality Score in Google AdWords?

A DigitalPoint member writes that he originally had managed an AdWords campaign across several domains and received a "Great" quality score for his keyword groups. However, ever since he has begun consolidating his AdWords campaigns on one domain, his quality score plummets. He writes:

We want to move everything to 1 domain name and build a large site around a premium domain name, but when I try sending all of the same ad groups/keywords to the same domain name, instead of the individual one like before our Quality Score plummets. Most keywords are then rated as OK and a decent amount are Poor. It takes a few days for this to happen though. Typically when I test with a new domain name we will have a “Great” Quality Score across the board for a day or two before it tanks and then traffic is basically gone. We literally receive about 1/100th of the traffic we were receiving before, yet the same ads, same keywords, same landing page etc. The only difference is we have everything going to the same domain name instead of individual domain names.

Clearly there is a domain name Quality Score that is affecting us. It seems when using individual domains names the success or failure of an individual ad group/keyword does not affect the others, but when it all goes to the same domain name it seems tied into each other.

It is assumed that his landing pages need more work, but he says that he has had the exact same landing pages on both domains. He speculates that a "new domain definatly resets the quality score."

It is possible that this is on the page level and that it may just be something that the user will need to wait for until the Quality Score updates (which is at least monthly):

I think it's at the page level. LP QS's are not updated that often (once a month, maybe more) so if your LP gets a poor QS you may be stuck with it until it's reevaluated. My hunch is that's why you see changes in the QS after campaigns have been live for few days.